1. Field of the Invention
The present invention relates to a safety clamp for anchoring a worker's safety tethering line to the skeleton of a building under construction. The clamp has jaws engaging the flanges of an I-beam, and an eye for receiving the tethering line or a component thereof, such as a snap hook.
2. Description of the Prior Art
The prior art has taken notice of the problem of protecting personnel working high above the ground on large structures. This situation is most frequently encountered in the field of construction of tall buildings. .A skeleton of steel members, such as I-beams and the like, is first erected. The balance of the building is supported by the skeleton.
Workers constructing and finishing the skeleton and building subsequent structures, such as poured concrete floor slabs, must work and be supported on the open skeleton. There is usually no floor, either temporary or final, to catch the worker should he or she fall.
Conventional prior art practice includes, among other measures, tethering a worker to the structure. This practice requires the presence of convenient anchor points secured to the skeleton.
An anchor and associated ancillary apparatus for this purpose is disclosed in U.S. Pat. No. 4,928,789, issued to Shane C. Claeys on May 29, 1990. The anchor comprises two jaws, essentially L-shaped, which are mutually connected, and adjusted toward and away from one another, by a screw. The screw is journaled in one jaw, and threads into the other.
U.S. Pat. No. 5,307,897, issued to C. Rockwell Turner et al. on May 3, 1994, discloses a stanchion attachable to an I-beam. The stanchion requires attachment at two points to the I-beam. At one of these points, a member is clamped to the I-beam by a screw secured in place by a lock nut. At the other point, a jaw engaging an I-beam flange is held in place by ratchet action.
This invention is large and cumbersome, and not readily deployed. Also, clamping apparatus operates differently from that of the present invention.
U.S. Pat. No. 5,092,426, issued to C. Anthony Rhodes on Mar. 3, 1992, discloses a safety system having a main channel member spanning two separated I-beams. This system requires a clamp or equivalent attachment at each of the two I-beams. Hooks for engaging the I-beam comprise right angled members, which are draped over horizontally and vertically arranged beams. This arrangement will not work with diagonally oriented beams, as will be encountered with wind brace beams. The hooks are also potentially susceptible to displacement from beneath, as might occur if a crane were being operated in the vicinity.
In the present invention, the hooks surround the I-beam. They are not dependent upon horizontal or vertical orientation, and are usable with diagonally disposed members.
The Rhodes invention is heavy, long, has projecting levers which are difficult to reach, and is difficult to maneuver, especially by one person.
U.S. Pat. No. 5,029,670, issued to Gerald T. Whitmer on Jul. 9, 1991, discloses a safety system which clamps to structural steel members and anchors a safety tether line. This system employs individual units which clamp to the flange of an I-beam or the like. In a fashion similar to that of the present invention, each unit has a jaw slidably mounted upon a square channel fastened to an opposing or corresponding jaw.
However, each unit is secured to the I-beam by two connections. In the first connection, opposed jaws are fastened in place by tightening a threaded fastener anchored within the movable jaw into the square channel, in the manner of a setscrew. In the second connection, a sandwich arrangement pinches the flange of the I-beam to the assembly including the stationary jaw.
This arrangement is considerably more cumbersome than the present invention, and relies on setscrew type connections for adherence to the I-beam.
A safety anchor accepting a tether line which anchor interfits slotted structural beams is seen in U.S. Pat. No. 5,156,233, issued to Gene E. Olson et al. on Oct. 20, 1992. This device works well within its intended application, but lacks means for clamping to ordinary structural members which do not have the specific slot with which this invention interfits.
P.C.T. Application No. PCT/US93/00960, dated Aug. 19, 1993, and U.K. Pat. Application No. 2,256,002, dated Nov. 25, 1992, disclose systems of anchors and associated safety tethering cables. These patents teach the use of one safety line strung among plural anchors, and separate tethering of a worker to the one safety line. These anchors are not disclosed as being similar to those of the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.